增压直喷汽油机燃油喷射特性对排放影响的试验研究

Experimental Study on the Influence of Fuel Injection Characteristics on Emissions of a Supercharged Direct Injection Gasoline Engine

基于某1.5 L涡轮增压直喷汽油机,搭建试验测试系统,采用试验匹配测试方法研究了喷油模式、喷油时刻、喷油比例、喷油压力等决定燃油喷射特性的关键参数对碳烟排放的影响。试验结果表明:单次喷油模式下在部分负荷时,喷油越提前,碳烟排放越多;在全负荷时,喷油越推迟,碳烟排放越多。在多次喷油模式下,随第一次喷油的推迟碳烟排放降低,随第二、三次喷油的推迟碳烟排放增加。提高喷油压力对部分负荷工况燃烧及排放改善不明显,但外特性工况碳烟排放显著下降,碳氢化合物排放总量也大幅度降低,缸内燃烧速度加快,燃烧稳定性提高,有效燃油消耗率降低约2%。

Using the test matching method,the influence of key fuel injection parameters,such as fuel injection mode,injection timing,fuel injection ratio,and injection pressure on soot emissions was studied on a test bench with a 1.5 L turbocharged direct injection gasoline engine.The test results show that for the single injection mode,the earlier the injection at part load,the more the soot emissions.At full load,the later the injection,the more the soot emissions.In the multiple injection mode,with the delay of first injection,soot emissions decrease,and with the delay of second and third injections,soot emissions increase.Increasing the injection pressure will not obviously improve the combustion and emissions under part load conditions,but will significantly reduce the soot and total hydrocarbon emissions under mapping conditions,and with the acceleration of combustion process in the cylinder and the improvement of combustion stability,brake specific fuel consumption will be reduced by approximately 2%.